Conveyance Drain Emitter

ABSTRACT

A rainwater conveyance system comprises a vault assembly and a drain emitter. At least a portion of the vault assembly is underground and is located above a percolation region in the ground. The drain emitter is connected to the conveyance line such that a primary portion of the collected water flows through the first portion of the conveyance line and a secondary portion of the collected water flows out of the second portion of the conveyance line through the drain emitter at a preset emitter flow rate. The drain emitter is arranged within the vault assembly, above the percolation region, and below the conveyance opening. The preset emitter flow rate is predetermined such that the flow of the secondary portion of the collected water out of the conveyance line through the drain emitter drains standing water from the conveyance line and the secondary portion of the collected water percolates through the percolation region.

RELATED APPLICATIONS

This application (Attorney's Ref. No. P220115) is a continuationapplication of U.S. patent application Ser. No. 16/848,112 filed Apr.14, 2020, currently pending.

U.S. patent application Ser. No. 16/848,112 is a continuationapplication of U.S. patent application Ser. No. 16/031,351 filed Jul.10, 2018, now U.S. Pat. No. 10,619,331, which issued on Apr. 14, 2020.

U.S. patent application Ser. No. 16/031,351 is a continuationapplication of U.S. patent application Ser. No. 15/093,611 filed Apr. 7,2016, now U.S. Pat. No. 10,017,920, which issued on Jul. 10, 2018.

U.S. patent application Ser. No. 15/093,611 claims benefit of U.S.Provisional Application Ser. No. 62/178,307 filed Apr. 7, 2015, nowexpired.

The contents of all related applications are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to rainwater collection systems andmethods and, more particularly, to rainwater collection systems andmethods adapted for use in cold environments.

BACKGROUND

Rainwater collecting on impermeable surfaces such as structures andpavement can create opportunities for water onsite reuse and problemsfor onsite or offsite storm water management systems. For both reuse andrainwater management, rainwater collecting on impermeable surfaces maybe channeled into a rainwater detention/retention tank. The rainwaterdetention/retention tank may be used to store and slowly releasecollected rainwater to the sewer or stormwater management system(detention) or to manage collected rainwater onsite through soilinfiltration, dispersion, and or recycling/reuse (retention). The term“storage tank” will be used herein to refer to a tank used for eitherrainwater detention or rainwater retention.

A storage tank is typically part of a larger rainwater collection systemcomprising ancillary components such as pipes, valves, pumps, and thelike. The storage tank itself and the ancillary components forming therainwater collection system may be made of any suitable material such asplastic, fiberglass, concrete, or steel.

At least some of a rainwater collection system, and often the entirerainwater collection system, is typically exposed to the elements. Thestorage tank and ancillary components forming the rainwater collectionsystem can thus be exposed to temperatures below the freezing point ofwater and thus are susceptible to damage when freezing water within therainwater collection system expands.

The need thus exists for systems and methods for reducing the risk thatrainwater collection systems will be damaged by freezing water.

SUMMARY

The present invention may be embodied as a rainwater conveyance systemfor managing water flowing through a conveyance line, where a firstportion of the conveyance line is located above ground and a secondportion of the conveyance line is located underground and above apercolation region in the ground. The rainwater conveyance systemcomprises a vault assembly and a drain emitter. At least a portion ofthe vault assembly is underground and is located above the percolationregion in the ground. The drain emitter is connected to the conveyanceline such that a primary portion of the collected water flows throughthe first portion of the conveyance line and a secondary portion of thecollected water flows out of the second portion of the conveyance linethrough the drain emitter at a preset emitter flow rate. The drainemitter is arranged within the vault assembly, above the percolationregion, and below the conveyance opening. The preset emitter flow rateis predetermined such that the flow of the secondary portion of thecollected water out of the conveyance line through the drain emitterdrains standing water from the conveyance line and the secondary portionof the collected water percolates through the percolation region.

The present invention may also be embodied as an emitter system forremoving standing water from a conveyance line operatively connectedbetween a downspout and a stormwater detention system, where at least aportion of the conveyance line is underground and is adjacent to apercolation region in the ground. The emitter system comprises a vaultassembly and a drain emitter. At least a portion of the vault assemblyis adapted to be buried underground. The drain emitter comprises anemitter housing and a flow control member supported by the emitterhousing to define an emitter opening. The drain emitter is adapted to beconnected to the conveyance line such that a primary portion of thecollected water flows to the stormwater detention system, a secondaryportion of the standing water flows continuously out of the conveyanceline through the emitter opening at a preset emitter flow rate, and thedrain emitter is arranged within the vault assembly, above thepercolation region, and below the conveyance opening. The flow controlmember is displaced relative to the emitter housing to set the presetemitter flow rate such that the secondary portion of the collected waterflows out of the drain emitter to drain standing water from theconveyance line and the secondary portion of the collected waterpercolates through the percolation region.

The present invention may also be embodied as a method of removingstanding water from a conveyance line operatively connected between adownspout and a stormwater detention system, where at least a portion ofthe conveyance line is underground and is adjacent to a percolationregion in the ground, the method comprising the following steps. A vaultassembly is provided, where at least a portion of the vault assembly isadapted to be buried underground. A drain emitter is provided, the drainemitter comprising an emitter housing and a flow control membersupported by the emitter housing to define an emitter opening. The drainemitter is operatively connected to the conveyance line such that aprimary portion of the collected water flows to the stormwater detentionsystem, a secondary portion of the standing water flows continuously outof the conveyance line through the emitter opening at a preset emitterflow rate, and the drain emitter is arranged within the vault assembly,above the percolation region, and below the conveyance opening. The flowcontrol member is arranged relative to the emitter housing to set thepreset emitter flow rate such that the secondary portion of thecollected water flows out of the drain emitter to drain standing waterfrom the conveyance line and the secondary portion of the collectedwater percolates through the percolation region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation, somewhat schematic view of a first exampleof a rainwater collection system of the present invention;

FIG. 2 is a side elevation, somewhat schematic view of a first exampleemitter system that may be used by the first example rainwatercollection system of the present invention; and

FIG. 3 is a side elevation, somewhat schematic view of a second exampleemitter system that may be used by the first example rainwatercollection system of the present invention.

DETAILED DESCRIPTION

Referring initially to FIG. 1 of the drawing, depicted therein is arainwater collection system 20 constructed in accordance with, andembodying, the principles of the present invention. The examplerainwater collection system 20 is configured to collect rainwater 22from a roof 24 of a structure 26. At least a portion of the examplerainwater collection system 20 is supported by and/or buried in theground 28.

a. General Operation of Rainwater Collection System

The example rainwater collection system 20 comprises at least onestorage tank 30, at least one conveyance system 32, a removal system 34,an overflow system 36, and at least one emitter system 38. The storagetank 30, conveyance system 32, removal system 34, and overflow system 36are or may be conventional, and examples of each are shown and describedherein only to that extent necessary for a complete understanding of thepresent invention. Two examples of the emitter system 38 forming part ofthe example rainwater collection system 20 of the present invention willbe described herein below.

In the following discussion, the term “flow rate” will generally be usedto refer to the flow of fluid such as water per unit time. In thecontext of a rainwater collection system such as the example rainwatercollection system 20, the term “maximum flow rate” refers to the maximumflow of fluid per unit time as determined by invariable designparameters of various components of the rainwater collection system. Theterm “preset flow rate” refers to the maximum flow of fluid per unittime as determined by the setting of one or more variable components ofthe rainwater collection system. The term “actual flow rate” refers tothe flow of fluid per unit time at a particular point in time and undera particular set of conditions and typically will be less than themaximum flow rate. The actual flow rate will typically vary depending onfactors such as amount and duration of rainfall, snow melt, or the like.

The example storage tank 30 comprises a bottom wall 40, a side wall 42,and a top wall 44. Water stored within the example storage tank 30defines a stored water level 46. A conveyance opening 50, a removalopening 52, and an overflow opening 54 are formed in the side wall 42 ofthe example storage tank 30. A given rainwater collection system 20 maycomprise more than one storage tank 30.

The overflow opening 54 defines a maximum water level 56 defined by thewater stored within the example storage tank 30, and the removal opening52 defines a minimum water level 58 defined by the water stored withinthe example storage tank 30. The example conveyance opening 50 is abovethe maximum water level 56. As will be described in further detailbelow, the stored water level 46 will typically vary over time betweenthe maximum water level 56 and the minimum water level 58 depending uponvarious environmental conditions such as amount of rainwater 22 thatfalls on the roof 24 and amount of water removed from the removalopening 52 over time.

FIG. 1 illustrates that the example conveyance system 32 comprises agutter 60 supported below edge of the roof 24 and a conveyance line 62operatively connected between the gutter 60 and the conveyance opening50 and between the gutter 60 and the emitter system 38. The exampleconveyance line 62 comprises a downspout 70 connected to the gutter 60,a buried pipe 72, a stand pipe 74, an inlet pipe 76 that extends throughthe conveyance opening 50, and a drop pipe 78 within the example storagetank 30. The example conveyance line 62 is sealed from the downspout 70to the drop pipe 78. The example conveyance line 62 is completely sealedand defines a conveyance water level 64 that corresponds to a verticalheight of the conveyance opening 50.

The example removal system 34 comprises an outlet pipe 80 that extendsthrough the removal opening 52, an outlet valve 82, and a removal pipe84. The outlet valve 82 controls flow of fluid out of the tank 30through the outlet pipe 80 and then out of the removal system 34 throughthe removal pipe 84. The removal pipe 84 may be connected to astormwater detention system (not shown) and/or a stormwater retentionsystem (not shown) for re-use or ground infiltration. The removal pipe84 may also be connected to the overflow system 36 as will be discussedbelow.

The example overflow system 36 comprises an overflow pipe 90 thatextends through the overflow opening 54 and an overflow line 92. Theoverflow system 36 is below the conveyance opening 50 and is configuredto allow water to be removed from the example storage tank 30 when thetank 30 is full to prevent back up of water into the conveyance system32. The overflow line 92 may be connected to a stormwater detentionsystem (not shown) and/or a stormwater retention system (not shown) forre-use or ground infiltration. The overflow line 92 may optionally beconnected to the removal pipe 84 of the removal system 34.

The emitter system 38 is connected to a bottom portion of the conveyanceline 62 to allow standing water within the conveyance line 62 to flowout of the conveyance line 62 at an emitter flow rate. A maximum emitterflow rate is predetermined based on the parameters of the rainwatercollection system 20, the percolation rate of the soil forming theground 28, and possibly environmental conditions such as weather. Apreset emitter flow rate is predetermined based on variable parametersof the emitter system 38. The emitter system 38 is in particularconfigured to remove water from the conveyance line 62 to prevent damageto the conveyance line 62 during freezing conditions.

The example rainwater collection system 20 operates basically asfollows. Rainwater 22 that falls on the roof 24 is collected by thegutter 60 and enters the conveyance line 62 as shown by arrow A. Aprimary portion of the collected water flows through the conveyance line62 and into the storage tank 30 as shown by arrow B at a conveyance flowrate. A secondary portion of the collected water flows out of theconveyance line 62 through the emitter system 38 as shown by arrow C ata preset emitter flow rate.

The maximum conveyance flow rate is determined by the parameters of theconveyance line 62 such as minimum cross-sectional area. The amount ofrain that falls on the roof 24 and is collected by the conveyance system32 and the amount of water removed by the removal system 34 and/oroverflow system 36 in a given time period will determine the actualconveyance flow rate of the conveyance system 32 and the stored waterlevel 46 within the storage tank 30.

The removal system 34 removes water from the storage tank 30 at aremoval flow rate as shown by arrow D. A maximum removal flow rate isdetermined by invariable parameters of the removal system 34 such asminimum cross-sectional area of piping and the like. A preset removalflow rate is determined by variable parameters of the removal system 34such as the cross-sectional area of a valve opening. Ideally, theremoval flow rate at which the removal system 34 removes water from thestorage tank 30 can be accommodated by the stormwater detention systemand/or stormwater retention system connected to the removal system 34.Also ideally, the storage tank 30 will be sized and dimensioned to storesufficient water during periods of heavy rain to accommodate the removalflow rate.

However, if the actual conveyance flow rate exceeds the preset removalflow rate for a sufficient period of time, the amount of water thataccumulates within the storage tank 30 will exceed the maximum waterlevel, and the overflow system 36 will remove water from the storagetank 30 as shown by arrow E to prevent over-filling of and possiblydamage to the storage tank 30.

Typically, the maximum conveyance flow rate will be much larger than thepreset removal flow rate from the removal system 34 but is sized to besubstantially equal to a maximum overflow flow rate of the overflowsystem 36. During normal operation of the rainwater collection system 20when collecting rainwater (e.g., water is flowing into the storagetank(s) 30), substantially all of the rainwater is conveyed by theconveyance system 32 to the storage tank(s) 30 and out of the storagetank(s) 30 by the removal system 34 and/or overflow system 36.

The preset emitter flow rate determined by the example emitter system 38is significantly less than both the maximum conveyance flow rate and theactual conveyance flow rate at any point in time. The preset emitterflow rate will typically also be significantly less than the presetremoval flow rate. Typically, the preset emitter flow rate ispredetermined such that normal collection and disposition of water bythe rainwater collection system 20 under most conditions issubstantially unaffected by the emitter system 38.

The emitter system 38 is connected at or near the lowest point of theconveyance line 62 such that hydrostatic pressure from the water shownby arrow A entering the conveyance system 32 will force water throughthe conveyance line 62 and into the tank(s) 30, with only a relativelysmall amount flowing into and out of the emitter system 38. However,when water is not entering the conveyance system 32, water stands withinthe conveyance line 62, initially at the conveyance water level 64.During freezing conditions, expansion of this standing water as itfreezes can pose a risk of damage to exposed components forming theconveyance line 62 such as the downspout 70 and stand pipe 74.

By removing standing water from the conveyance line 62 at the presetemitter flow rate, the emitter system 38 encourages water movementwithin the conveyance line 62 and will remove such standing water fromthe conveyance line 62 after a sufficient time period, assuming no newwater is introduced into the conveyance line 62 (unlikely duringfreezing conditions). Both water movement and eventual removal of thestanding water discourage freezing of water within the conveyance line62 and thus reduce the likelihood of damage to the components of theconveyance line 62.

The actual conveyance flow rate, actual removal flow rate, actualoverflow flow rate, and actual emitter flow rate will depend uponenvironmental factors such as rainwater collected over a given period oftime. The maximum conveyance flow rate, preset removal flow rate,overflow flow rate, and preset emitter flow rate will depend upon theparameters of a specific rainwater collection system constructed inaccordance with the principles of the present invention.

In the example rainwater collection system 20, the preset emitter flowrate is approximately 1 gallon per hour but in any event may be within afirst range of substantially between 0.5 gallons per hour to 3 gallonsper hour or within a second range of substantially between 0.1 gallonsper hour to 10 gallons per hour. The preset emitter flow rate may bepredetermined to empty the conveyance line 62 of standing water inapproximately 8 hours but in any event should empty the conveyance line62 within a first time range of substantially between 6 and 10 hours ora second time range of substantially between 2 and 16 hours. In general,a rainwater collection system of the present invention may have a presetemitter flow rate that is substantially between within a first range of0.1% to 5% of the maximum conveyance flow rate. In any event, the presetemitter flow rate may be within a second range of substantially between0.1 and 20% of the maximum conveyance flow rate.

To summarize, the example emitter system 38 is designed to work with awet conveyance piping network such as the conveyance line 62 for arainwater harvesting system such as the example rainwater collectionsystem 20. The emitter system 38 allows water to flow to the storagetank(s) 30 when it is raining, though will drain the majority of thewater within the wet conveyance line over the course of a designatedtime once it stops raining.

The purpose of the example emitter system 38 is thus to drain rainwaterfrom the conveyance line 62 during winter months to prevent damage topipes, valves, and fittings from freezing weather, while still allowingmost of the rain to go to the storage tank during rain events. Theexample emitter system 38 is typically affixed at the lowest point ofthe conveyance system and in a location where it can be easily accessed.The device may optionally be housed in an irrigation box if belowground. The area below the emitter system is typically dug out and atleast partly covered with drain rock to facilitate drainage of wateraway from the irrigation box as it empties from the emitter system 38.

With the foregoing general understanding of the construction andoperation of the example stormwater detection system 20 in mind, thedetails of two examples of emitter systems that may be used as theexample emitter system 38 will now be described.

II. First Example Emitter System

Referring now to FIG. 2 of the drawing, depicted therein is a firstexample emitter system 120 that may be used as the example emittersystem 38 of the example stormwater detention system 20. The firstexample emitter system 120 comprises an emitter assembly 122, an emitterinlet line 124, an optional vault assembly 126, and an emitterpercolation region 128. The emitter inlet line 124 is connected to theconveyance line 62 such that water flowing through the conveyance line62 also flows to the emitter assembly 122. The example emitter assembly122 is arranged within the vault assembly 126, and the vault assembly126 is arranged above the emitter percolation region 128.

The first example emitter system 120 operates basically as follows.Water from the conveyance line 62 flows through the emitter inlet line124 to the emitter assembly 122. The water flowing through the waterinlet line 124 will flow out of the emitter inlet outlet assembly 122 atthe preset emitter flow rate. Water flowing out of the emitter assembly122 enters the percolation region 128 and percolates into the ground 28.

With the foregoing general understanding of the first example emittersystem 120 in mind, the details of the construction and operation of thefirst example emitter system 120 will now be described in furtherdetail.

The example emitter assembly 122 comprises an emitter housing 130 and aflow control member 132. The emitter housing 130 and flow control member132 cooperate to define an emitter opening 134. The example emitterassembly 122 may be a conventional drip emitter designed for use withirrigation systems. An optional emitter filter member 136 may bearranged upstream of the emitter opening 134. The optional filter member136 may be a wire mesh filter, a porous material (e.g., open-cell foamor porous solid material such as ceramic, metal, or plastic) or fibrousmaterial (e.g., geotextile filter fabric) capable of impeding orrestricting flow of water and preventing organic debris from cloggingemitter opening 134, without substantially degrading over time.

The emitter inlet line 124 comprises an emitter inlet pipe 140, aconveyance T-fitting 142 (FIG. 1), and an emitter internal fitting 144.The conveyance T-fitting 142 is connected to the conveyance line 62, andthe emitter inlet pipe 140 is connected between the conveyance T-fitting142 and the emitter internal fitting 144. The conveyance T-fitting 142should be located at the lowest point of the conveyance line 62 orpossibly near the lowest point of the conveyance line 62 if so long asthe conveyance T-fitting 142 can be insulated from ambient air (e.g.,underground). In any event, the example emitter internal fitting 144 isconfigured and arranged to support the emitter housing 130 within theemitter vault assembly 126 above the emitter percolation region 128.

The example emitter vault assembly 126 comprises a vault housing 150 anda vault lid 152 and defines an emitter vault chamber 154. The vaulthousing 150 has a vault bottom opening facing the emitter percolationregion 128 and vault top opening that may be selectively covered by thevault lid 152. The example emitter vault chamber 154 provides a volumeof space in which a portion of the emitter line 124 extends. In thefirst example emitter system 120, the example emitter housing 130, flowcontrol member 132, and optional bypass valve 148 are located with theemitter vault chamber 154.

Removal of the vault lid 152 (open configuration) thus facilitatesaccess to the emitter housing 130 and flow control member 132 andoptional bypass valve 148 through the top opening defined by the vaulthousing 150. With the vault lid 152 in place over the vault top opening(closed configuration), the vault chamber 154 is enclosed and insulatedfrom ambient temperatures. Mulch, gravel, dirt or the like may be placedon top of the vault lid 152 in its closed configuration to provideadditional insulation between ambient air and the vault chamber 154 butremoved to allow removal of the vault lid and access to the vaultchamber 154.

The example emitter percolation region 128 comprises a first percolationlayer 160 of the ground 28 under the vault assembly 126. To improvepercolation of water into the percolation region 128, a secondpercolation layer 162 of material such as drain rock 164 may be arrangedon top of the first percolation layer 160 and below open bottom of thevault assembly 126. The percolation layer 128 should be designed asnecessary to percolate water flowing out of the emitter assembly 122 atthe emitter flow rate.

Optionally, an emitter line 170 comprising an emitter intermediate pipe172, a bypass valve 174, and an emitter outlet pipe 176 may be connectedto the emitter assembly 122. If the optional emitter intermediate pipe172, bypass valve 174, and emitter outlet pipe 176 are used, the emitterinternal fitting 144 is a T-fitting, and the emitter intermediate pipe172 is connected between the emitter internal fitting 144. The bypassvalve 174 is connected between the emitter intermediate pipe 172 and theemitter outlet pipe 176. The emitter line 170 may optionally furthercomprise an overflow T-fitting 178 that allows the emitter outlet pipe176 to be connected to the overflow line 92 as shown in FIG. 1. Removalof the vault lid 152 (open configuration) also facilitates access to thebypass valve 174 through the top opening defined by the vault housing150.

In use, the emitter housing 130 is connected to the emitter internalfitting 144 with the emitter opening 134 at the bottom of the emitterhousing 130. The flow control member 132 and, if used, the optionalemitter filter 136 may be configured to set the preset emitter flow rateat which water flows through the emitter line 124, through the emitterhousing 130, and out of the emitter opening 134. The example flowcontrol member 132 is rotated relative to the emitter housing 130 to setthe preset emitter flow rate. The preset emitter flow rate should bepredetermined to allow sufficient flow of water out of the conveyanceline 62 to prevent freezing of standing water within the conveyance line62 but not to exceed the rate at which water percolates into thepercolation region 128.

In addition, in anticipation of periods of extended freezing, theoptional bypass valve 148 may be operated to drain the conveyance line62 as shown by arrow F in FIG. 1 and eliminate any possibility offreezing of the water within the conveyance line 62.

III. Second Example Emitter System

Referring now to FIG. 3 of the drawing, depicted therein is a secondexample emitter system 220 that may be used as the example emittersystem 38 of the example stormwater detention system 20. The secondexample emitter system 220 comprises an emitter assembly 222, an emitterinlet line 224, a vault assembly 226, and an emitter percolation region228. The emitter inlet line 224 is connected to the conveyance line 62such that water flowing through the conveyance line 62 also flows to theemitter assembly 222. The example emitter assembly 222 is arrangedwithin the vault assembly 226, and the vault assembly 226 is arrangedabove the emitter percolation region 228.

The second example emitter system 220 operates basically as follows.Water from the conveyance line 62 flows through the emitter inlet line224 to the emitter assembly 222. The water flowing through the waterinlet line 224 will flow out of the emitter inlet outlet assembly 222 atthe preset emitter flow rate. Water flowing out of the emitter assembly222 enters the percolation region 228 and percolates into the ground 28.

With the foregoing general understanding of the second example emittersystem 220 in mind, the details of the construction and operation of thesecond example emitter system 220 will now be described in furtherdetail.

The example emitter assembly 222 comprises an emitter housing 230 and anemitter cap 232. The example emitter cap 232 defines an emitter opening234. An optional emitter filter member 236 may be arranged upstream ofthe emitter opening 234. The example emitter cap 232 is formed by anoff-the-shelf pipe fitting designed to prevent fluid flow but in which ahole has been formed to define the emitter opening 234. The optionalfilter member 236 may be a wire mesh filter, a porous material (e.g.,open-cell foam or porous solid material such as ceramic, metal, orplastic) or fibrous material (e.g., geotextile filter fabric) capable ofimpeding or restricting flow of water and organic debris from cloggingopening 234, without substantially degrading over time.

The emitter inlet line 224 comprises an emitter inlet pipe 240, aconveyance T-fitting 242 (FIG. 1), and an emitter internal fitting 244.The conveyance T-fitting 242 is connected to the conveyance line 62, andthe emitter inlet pipe 240 is connected between the conveyance T-fitting242 and the emitter internal fitting 244. The example emitter internalfitting 244 is configured and arranged to support the emitter housing230 within the emitter vault assembly 226 above the emitter percolationregion 228.

The example emitter vault assembly 226 comprises a vault housing 250 anda vault lid 252 and defines an emitter vault chamber 254. The vaulthousing 250 has a vault bottom opening facing the emitter percolationregion 228 and vault top opening that may be selectively covered by thevault lid 252. The example emitter vault chamber 254 provides a volumeof space in which a portion of the emitter line 224 extends. In thesecond example emitter system 220, the example emitter housing 230,emitter cap 232, and optional bypass valve 248 are located with theemitter vault chamber 254. Removal of the vault lid 252 (openconfiguration) thus facilitates access to the emitter housing 230, flowcontrol member 232, and bypass valve 248 through the top opening definedby the vault housing 250. With the vault lid 252 in place over the vaulttop opening (closed configuration), the vault chamber 254 is enclosedand insulated from ambient temperatures. Mulch, gravel, dirt or the likemay be placed on top of the vault lid 252 in its closed configuration toprovide additional insulation between ambient air and the vault chamber254 but removed to allow removal of the vault lid and access to thevault chamber 254.

The example emitter percolation region 228 comprises a first percolationlayer 260 of the ground 28 under the vault assembly 226. To improvepercolation of water into the percolation region 228, a secondpercolation layer 262 of material such as drain rock 264 may be arrangedon top of the first percolation layer 260 and below the vault assembly226. The percolation layer 228 should be designed as necessary topercolate water flowing out of the emitter assembly 222 at the presetemitter flow rate.

Optionally, an emitter line 270 comprising an emitter intermediate pipe272, a bypass valve 274, and an emitter outlet pipe 276 may be connectedto the emitter assembly 222. If the optional emitter intermediate pipe272, bypass valve 274, and emitter outlet pipe 276 are used, the emitterinternal fitting 244 is a T-fitting, and the emitter intermediate pipe272 is connected between the emitter internal fitting 244. The bypassvalve 274 is connected between the emitter intermediate pipe 272 and theemitter outlet pipe 276. The emitter line 270 may optionally furthercomprise an overflow T-fitting 278 that allows the emitter outlet pipe276 to be connected to the overflow line 92 as shown in FIG. 2.

In use, emitter housing 230 is connected to the emitter internal fitting244 with the emitter opening 234 at the bottom of the emitter housing230. The emitter opening 234 formed in the emitter cap and, if used, theoptional emitter filter 236 may be configured to prevent debris fromclogging opening 234 and to set the preset emitter flow rate at whichwater flows through the emitter line 224, through the emitter housing230, and out of the emitter opening 234. The emitter opening 234 may beformed, for example, by drilling a hole in the emitter cap 232 having adiameter to determine or preset a maximum emitter flow rate, and thenthe preset emitter flow rate may be adjusted (reduced) using the emitterfilter 236. The preset emitter flow rate should be predetermined toallow sufficient flow of water out of the conveyance line 62 to preventfreezing of standing water within the conveyance line 62 but not toexceed the rate at which water percolates into the percolation region228.

In addition, in anticipation of periods of extended freezing, theoptional bypass valve 248 may be operated to drain the conveyance line62 and eliminate any possibility of freezing of the water within theconveyance line 62.

IV. Additional Considerations

In the example rainwater collection system 20, portions of theconveyance line 62 and the entire emitter system 38 are arrangedunderground. In other rainwater collection systems to which theprinciples of the present invention may be applied, the entireconveyance line 62 and the emitter system 38 may be arranged aboveground. The emitter system 38 would work in the same basic manner aboveground as below ground, but an above ground emitter system will be moresusceptible to multiple brief freezing events or unexpected, quick-onsetfreezing events that cause standing water within the conveyance line 62to freeze before the emitter system 38 can sufficiently drain suchstanding water.

Further, in addition or instead, either of the example emitter systems120 or 220 may be used as one or more removal emitter systems todisperse water exiting the tank(s) 30 through the removal system 34. Inthis case, the emitter systems 120 and 220 would be connected to theremoval system 34 and arranged at one or more removal emitter locationshaving sufficient permeability to allow water to permeate into theground 26. The preset flow rate of such a removal emitter system wouldbe sized and dimensioned as appropriate for the permeability of thesource emitter location(s) but could be as high as 100% of theconveyance flow rate should permeability of the removal emitter locationallow.

What is claimed is:
 1. A rainwater conveyance system for managing water flowing through a conveyance line, where a first portion of the conveyance line is located above ground and a second portion of the conveyance line is located underground and above a percolation region in the ground, the rainwater conveyance system comprising: a vault assembly, where at least a portion of the vault assembly is underground and is located above the percolation region in the ground; and a drain emitter connected to the conveyance line such that a primary portion of the collected water flows through the first portion of the conveyance line; and a secondary portion of the collected water flows out of the second portion of the conveyance line through the drain emitter at a preset emitter flow rate; wherein the drain emitter is arranged within the vault assembly and above the percolation region, and connected to the conveyance line such that the second portion of the conveyance line defines an emitter inlet and an emitter outlet; and the preset emitter flow rate is predetermined such that the collected water flows into the drain emitter within the vault assembly through the emitter inlet to allow the primary portion of the collected water to flow out of the drain emitter and the vault assembly through the emitter outlet; and the secondary portion of the collected water to flow out of the conveyance line through the drain emitter to drain standing water from the conveyance line, where the secondary portion of the collected water percolates through the percolation region.
 2. A rainwater conveyance system as recited in claim 1, in which the conveyance line defines a maximum conveyance flow rate; and the preset emitter flow rate is within a range of between 0.1% and 20% of the maximum conveyance flow rate.
 3. A rainwater conveyance system as recited in claim 1, in which: the conveyance line defines a maximum conveyance flow rate; and the preset emitter flow rate is within a range of between 0.1% and 5% of the maximum conveyance flow rate.
 4. A rainwater conveyance system as recited in claim 1, in which the preset emitter flow rate is within a range of between 0.1 gallons per hour and 10 gallons per hour.
 5. A rainwater conveyance system as recited in claim 1, in which the preset emitter flow rate is within a range of between 0.5 gallons per hour and 3 gallons per hour.
 6. A rainwater conveyance system as recited in claim 1, in which the preset emitter flow rate is selected to drain standing water from the conveyance line in a time range of between 2 hours and 16 hours.
 7. A rainwater conveyance system as recited in claim 1, in which the preset emitter flow rate is selected to drain standing water from the conveyance line in a time range of between 6 hours and 10 hours.
 8. A rainwater conveyance system as recited in claim 1, in which the drain emitter comprises: an emitter housing; and a flow control member; wherein the flow control member and the emitter housing cooperate to define an emitter opening through which the secondary portion of the collected water flows out of the drain emitter.
 9. A rainwater conveyance system as recited in claim 8, in which the flow control member is rotated relative to the emitter housing to set the preset emitter flow rate.
 10. A rainwater conveyance system as recited in claim 9, in which the drain emitter further comprises an emitter filter arranged to filter the secondary portion of the collected water before the secondary portion of the collected water flows through the emitter opening.
 11. An emitter system for removing standing water from a conveyance line operatively connected between a downspout and a stormwater detention system, where at least a portion of the conveyance line is underground and is adjacent to a percolation region in the ground, the emitter system comprising: a vault assembly, where at least a portion of the vault assembly is adapted to be buried underground; a drain emitter comprising an emitter housing, and a flow control member supported by the emitter housing to define an emitter opening; wherein the drain emitter is adapted to be connected to the conveyance line such that a primary portion of the collected water flows to the stormwater detention system, a secondary portion of the standing water flows continuously out of the conveyance line through the emitter opening at a preset emitter flow rate, and the drain emitter is arranged within the vault assembly and above the percolation region; and the flow control member is displaced relative to the emitter housing to set the preset emitter flow rate such that the secondary portion of the collected water flows out of the drain emitter to drain standing water from the conveyance line, and the secondary portion of the collected water percolates through the percolation region.
 12. An emitter system as recited in claim 11, in which: the conveyance line defines a maximum conveyance flow rate; and the preset emitter flow rate is within a range of between 0.1% and 20% of the maximum conveyance flow rate.
 13. An emitter system as recited in claim 11, in which: the conveyance line defines a maximum conveyance flow rate; and the preset emitter flow rate is within a range of between 0.1% and 5% of the maximum conveyance flow rate.
 14. An emitter system as recited in claim 11, in which the preset emitter flow rate is within a range of between 0.1 gallons per hour and 10 gallons per hour.
 15. An emitter system as recited in claim 11, in which the preset emitter flow rate is within a range of between 0.5 gallons per hour and 3 gallons per hour.
 16. An emitter system as recited in claim 11, in which the preset emitter flow rate is selected to drain standing water from the conveyance line in a time range of between 2 hours and 16 hours.
 17. An emitter system as recited in claim 11, in which the preset emitter flow rate is selected to drain standing water from the conveyance line in a time range of between 6 hours and 10 hours.
 18. An emitter system as recited in claim 11, further comprising an emitter filter arranged to filter the secondary portion of the collected water before the secondary portion of the collected water flows through the emitter opening.
 19. A method of removing standing water from a conveyance line operatively connected between a downspout and a stormwater detention system, where at least a portion of the conveyance line is underground and is adjacent to a percolation region in the ground, the method comprising the steps of: providing a vault assembly, where at least a portion of the vault assembly is adapted to be buried underground; providing a drain emitter comprising an emitter housing, and a flow control member supported by the emitter housing to define an emitter opening; operatively connecting the drain emitter to the conveyance line such that a primary portion of the collected water flows to the stormwater detention system, a secondary portion of the standing water flows continuously out of the conveyance line through the emitter opening at a preset emitter flow rate, and the drain emitter is arranged within the vault assembly and above the percolation region; and arranging the flow control member relative to the emitter housing to set the preset emitter flow rate such that the secondary portion of the collected water flows out of the drain emitter to drain standing water from the conveyance line, and the secondary portion of the collected water percolates through the percolation region.
 20. A method as recited in claim 19, further comprising the step of arranging an emitter filter to filter the secondary portion of the collected water before the secondary portion of the collected water flows through the emitter opening.
 21. A rainwater conveyance system for managing water flowing through a conveyance line, where a first portion of the conveyance line is located above ground and a second portion of the conveyance line is located underground and above a percolation region in the ground, the rainwater conveyance system comprising: a vault assembly, where at least a portion of the vault assembly is underground and is located above the percolation region in the ground; and a drain emitter comprising an emitter housing and a flow control member, where the drain emitter is connected to the conveyance line such that a primary portion of the collected water flows through the first portion of the conveyance line; and a secondary portion of the collected water flows out of the second portion of the conveyance line through the drain emitter at a preset emitter flow rate, and the flow control member and the emitter housing cooperate to define an emitter opening through which the secondary portion of the collected water flows out of the drain emitter; wherein the drain emitter is arranged within the vault assembly and above the percolation region; and the preset emitter flow rate is predetermined such that the flow of the secondary portion of the collected water out of the conveyance line through the drain emitter drains standing water from the conveyance line; and the secondary portion of the collected water percolates through the percolation region.
 22. A rainwater conveyance system as recited in claim 21, in which the flow control member is rotated relative to the emitter housing to set the preset emitter flow rate.
 23. A rainwater conveyance system as recited in claim 22, in which the drain emitter further comprises an emitter filter arranged to filter the secondary portion of the collected water before the secondary portion of the collected water flows through the emitter opening. 